You can surely mate, a lot of people (myself included) have done this. I haven't gone the whole hog yet and wired in the second reverse light to it, but have just fitted a red bulb in there for the mean time (thanks Lenny!).

Think Charlie (username Brigante) has got detailed pics of this mod in his build thread. He used a replica part and has no issues with it, think genuine Ford ones are considerably dearer. I'll root out some links of his thread and of buying options. The bay is probably your best bet, or else keep an eye on forum classifieds.

By the way, you may already know this anyway, but the Mk2 units are the same as those used on the previous Mk1 and 1.5 models, just in case it broadens your search a bit.